HYPONATREMIA

Hyponatremia Hyperglycemia Hypertriglyceridemia Renal (UNa >20, FENa >1%) Osmotic diuresis (Eg. Diabetic Ketoacidosis*) Hypoaldosteronism Diuretics Polyuric Acute Tubular Necrosis Extra renal (UNa<10, FENa <1%) GI losses (gastroenteritis*, pyloric stenosis*) Insensible losses (Cystic Fibrosis*, Burns*) SiADH Endocrinopathies Adrenal insufficiency (Low UNa esp. <20): Congestive heart failure* Nephrotic syndrome* Nephritis syndrome* Sepsis* with capillary leak ADH suppressed ADH present Polydipsia Decreased osmolar intake Abuse/neglect* Inappropriate formula Water intoxication Abuse/neglect* Inappropriate formula Iatrogenic *Indicates Key Condition This is not an exhaustive list of medical conditions. True Hyponatremia Pseudo-Hyponatremia Is this TRUE hyponatremia? Posm low Check plasma osmolality Posm normal or high Is ADH appropriately suppressed? Check urine osmolality Urine osmolality <100 Urine osmolality >100 Hypovolemic Euvolemic Hypervolemic Why is ADH present? Check clinical volume status Low intravascular volume (↓EABV) High intravascular volume (↑EABV) (UNa >20, FENa >1%): Renal Failure*